Feed pump for combustion engines



Aug. 28, 1923. A

' F. EGERSDRFER v FEED ,PUMP FOR COMBUSTION ENGINES Filedv sept. 10 1920 2 Sheets-Sheet 1 lili. NN

Aug. 2s, 1923. .,466,092

F. EG ERSDORFER FEED PUMP FOR COMBUSTION ENGINES v Filed Sept. lO, 1920 2 Sheets-Sheet 2 Patented Aug. 281, i923.

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Application filed September 10, 1920. Serial No. 409,503.

(GRANTED UNDER. 1HE PROVISINS OFTHE ACT 0F MARCH 3, 1921, 41 STAT. L., 1313.)

To all whom. t may concer/n:

Be it known that l, FRITZ EGERSDRFER, a citizen of Germany, residing at Charlottenburg, Germany, have linvented certain 5 new and useful Improvements in Feed Pumps for Combustion Engines (for which i filed application in Germany, filed July 20, 1914, blo-303,205, and application in Germany, filed March 15, 1917, No. 360,- 863; application in F rance, filed May 30, l1919, vNol 518,583; application in Great Britain, tiled July 9, 1920, No. 148,157; application in Italy, filed Sept. 10, 1919, No. 275,151; application. in Sweden, filed April 24, 1919, No. 48,684; application in Norway, filed May 16, 1919, No. 36333; application in Denmark, filed May 5th, 1919, No. 30137; application in Spain, tiled May 23,1919, No. 69865; application in Switzer- -land, filed May 10, 1919, No. 94534; application in Czechoslovakia, filed September 5, 1919 (not yet allowed) .application in Holland, iled June 6, 1919, No 8005); and I do hereby declare the following to bea full, clear, and exact description of the invention, such as will enable others skilled in the art to whichnit appertains to make and use the same.

My invention relates to improvements in feed pumps for internal-combustion engines. It has heretofore been proposed to feed the motor charge to internal-combustion engines by means of` small pumps provided with reclprocating pistons. I have found that theoperation of .such feed pumps is unsatisfactory, because, by reason ofthe suction and pressure valves provided in the pump, it is impossible to feed accurate amounts of fuel to the engine,-amounts which frequently are not more than a fractionA of a cubic centimeter. Furthermore feed pumps of this construction are objectionable by rea- -son of the high number of .revolutions of the engine and` the high number ofthe vstrokes required of the pump, which under normal conditions amounts to 500 per minute and more. The object of the improvements is to projlde vapparatus for feeding fuel, air, or combustible mixture to the motor cylinder, adapted to feed accurately measured amounts tol the cylinder, and

which need not be more than a fraction of .a cubic centimeter, and apparatus which can be -operated at high speed. With-this object in view my invention consists in connecting the fuel supply pipe to the motor through a rotary pump. A rotary pump is a valveless pump, it can be operated at high speed, because its movable parts are always moving in the same direction and it is not subiect to inertia, and it is adapted to supply minimum and measured amounts of fuel or air or combustible mixture at maximum speed. rlhe amount of air or fuel or combustible mixture supplied by the rotary pump can be varied from zero to a maximum, so that the pump answers all requirements lof the operation of the engine. The movable parts of the pump are perfectly enclosed within a 'V casing and`they require no lubrication, be-

cause .they are lubricated by the fuel itself.

The rotary pump may communicate directly with the cylinder of the combustion vengine without the necessity of providing check valves between, and the fuel may be projected directly into the cylinder, so that the objectionable long suction pipes'and other objectionable chambers are ydispensed with.

My invention also relates to an improved construction of the pump which particularly adapts the same. to be used as a feed pump for internal-combustion engines. Particularly in case of small engines operated at high speeds, each charge of the cylinder requires' a very small amount of fuel to be supplied. In such cases rotary pumps of the construction now in use are not well adapted to be used as feed pumps, because they cannot feed such small amounts. Furthermore it is not possible by means of such pumps to vary the amount of fuel for each stroke and thereby to regulate the sup- O ply of fuel to the motor. For example, if an Ainternal-combustion engine consumes for `each H. P. per hour 230 grammes of benzine, a four cylinder motor of 15H. P. and

1000 revolutions `per -minute .consumes 24,50 grammes of benzine] per hour. Therefore each cylinder consumes 863 grammes per hour or about 15 grammes per minute. As the cylinder .performs 500 suction strokes per minute each stroke consumes- 0L03 of a pumps of known construction such a' sinall and accurately measured amount cannot be fed to .the cylinder', even if the said pumps are provided with a single valve,-tliis because of leakage and inaccurate operation of the rotating parts. Regulation of such a small amount is impossible, because regulating mechanisms do not operate with sucient accuracy, and as far as l am aware such regulating apparatus has not heretofore been provided.

l have found that all requirements of successful 4operation of an internal-combustion engine are fully 4answered by a rotary pump of that class in which one or more pistons or plungers are mounted for reciprocation within a rotary drum and eccentrically of the axis of rotation, and in which a cam disk is provided for reciprocating the said pistons or plunger-s, the cam disk being adapted to be changed in its relative position for of rotation, the stroke of the pistons or plungers within their cylindrical chambers is zero, so that no fuel is fed to the cylinder.

Proportionately as the inclination of the cam is increased, the piston stroke is increased and the amount of duid supplied by the pump is increased.

It will therefore be understood, that the amount of fluid' supplied by tlie pump may be regulated from zero to a maximum inde-- pendently of the number of revolutions. As the cam does not take part in the rotation of the pump and is stationaryrelatively tothe pump, it may be so connected with the governoi' of the engine, that the fuel supplied -to the cylinder will be automatically controlled bythe said governor.

The said construction of the rotary pump is particularly adapted for use in connection with multi-cylinder engines, because in such engines for each cylinder a pump piston or plunger may beiprovided within the same rotary member, and the cylindrical chambers of plungers will then lbe connected one with each of the motor cylinders. Therefore a single pump is provided for all the cylinders, but each cylinder receives its fuel, or

air, or combustible mixture independently of the other cylinders. Thereby premature combustion of the fuel or combustiblemixture and whirls within the supply pipes to `performing the pressure stroke. ingly only the pocket13 within which thev :incense I the cylinders and accordingly non-uniform supply and non-uniform operation of the motor are avoided.

The pump is such as is described in my copending application for United States Let-v ters Patent filed ISeptember 10th,- 1920, Serial No. 409,504. v

For the purpose of explaining the invention several examples embodying the same are lshown in ythe accompanying drawings..

ln said drawings- F igr 1 is a longitudinal section of a feed prgvided' with with automatic setting mechanism for the cam and in connection with a carbureter,

Figs. 6 to 9 are cross-sections of the pump showing several examples of the construction of the inlet land outlet ports, and

. Fig. 10 is a longitudinal section showing a modificationof the piston of the pump.

The same numerals of-reference have been used in all `the'views to indicate correspondin parts.

ferring to the example shown in Fig. l, toa rotary shaft 10 a rotary body or drum 11. is secured which is rotatably mounted within a cylindrical casing 12 ndis formed with two cylindrical chamber or' pockets 13 disposedlengthwise and eccentrically of the axis of rotation of the drum. Within each of the said pockets a plunger or piston is mounted for reoiprocation, and one of the said plungers which has been indicated by .the numeral 111 ris the feeding plunger,

lWhile the other'one which has been indicated by the numeral l5 is.. provided for retracting the plunger 14 from its pocket after Accordplunger 14 is located is adapted to be alternately connected `witlrinlet and outlet ports, while the pocket 13 containing the plunger 15 is closed 'as against said ports. The ends of the plu -rs 14 and 15 which project from the cylindrical chambers 13 carry slide shoes 16 which have universal movementon the plungers and which have flat sliding or bearing faces. As shown the plungers and shoes 16 have spherical bearing surfaces. The flat sliding vor bearing faces of the shoes 16 are engaged by a cam 17 which as shown is in the form of an iiiclined disk. The said disk 17 is made inill ' 24 alternately.

tegral-With two-pivots 18 and 19 (Figs. 2 and 3) by means of which the said disk is supported 'Within Suitable bearings provided in the wall of the casing 12. By thus being supported on the pivots 18 and 19 the disk 17 may be rocked in such a Way, that the plain cam face of the disk which en'- gages the slide shoes 16 may be set either in a position perpendicular to the axis of rotation of the drum 11, or in any position inclined to the said axis. An inclined position is shown in Fig. 1. The plungers 14 'and 15 are connected by a rocker 20 which is supported on the rotary parts 10, 11. In the construction shown in Fig. 1 the said rocker is mounted Within a slot formed in the shaft 10. rThe rocker is so connected with the plungers 14 and 15, as to transmit movement from one to the other, so that the plungers move in opposite directions. When the drum 11 is rotated by suitable mechanism, for example by means of a gear wheel 21, the plungers 14 and 15I slide with their shoes 16 on the inclined cam disk 17 and in such movement the plungers 14 and 15 are always held in Contact with the cam disk by means of the rocker 20, so that the rotary movement of the drum 11 'is transformed into reciprocating movement of the pluners.

The feed pump shown in Fig. 1 is designed for use in connection with a two-cylinder motor performing successive suction strokes. A motor of this construction requil-es a single feed plunger 14 when the number of revolutions ofthe pump is one half of that of the engine. Therear end of the cylindrical pocket 13 of the plunger 14 is adapted to be connected by a port 22 with a pressure passa 23 and a suction passage n the preferred form shown in Fig. 1 the said pressure and suction passages are formed in a removable annular disk 25, which is shown in detail in Fig. 6.

For setting the cam disk 17 in its different inclined positions'the outer end of the pivot 18 carries a toothed sector 26 which is adapted to be operated by a worm 27. The worm 27 can be operated in different Ways. In the example shown in Fig. 3 it carries a milled disk 28 for operation of the worm by hands( pump,

ln the modification shown in Fig. 2, instead of the worm 27 a crank29 is secured to the shaft` 18, and inthe modification shown in Fic', 3a the Worm 27 is connected with a v30 and it is discharged therefrom through a passage 31. The latter is'co'nnected with a nozzle 32, as is shown in Fig-4, which by As appears from Fig. 4, the nozzle 32 is v v disposed Within the `-inixing 'chamber of a carbureter 33, and Within the ksaid mixing chamber a disk 34 is disposed in front of the discharge end of the nozzle, by means of which the fuel supplied to the mixing chamber is sprayed into the surrounding air. For driving the pump the gear wheel 21 keyed to the shaft 10` is in engagement with a gear Wheel 35 which is in mesh with a gear Wheel 36 keyed to the gear shaft of the enine. g For regulating the amount of fuel supplied by tlie pump the cam disk 17 is rocked more or less by means ofthe milled head '28 orl the crank 29 vor 29. shown in Figs. 4 and 5 the crank 29 is connected by a rod-37 with a crank 38 connected with the governor. Therefore the cam disk is set and the Supply of fuel regulated automatically by the governor. y

For varying the supply of air according 'to the supply ofl fuel the inlet to the carbureter 33 1s provided with a throttle member 39, which as shown is connected by a lever 40 and a link 41 with the rod 37, so that the said throttle member is set together with the cam.

ln the example shown in Fig. 5 the Whole stroke of the feed plunger 14 is used for su plying the fuel to the cylinders. ln Fig. 7 l have shown by way of modificationy a pump designed for feeding fuel to a onecylinder internal-combustion engine. In this case fthe pressure passage 23 and the suction passage 24 formed through ldisk 25 extend, not as in Fig. 6 through approximately 1801of the circumferential path of port 22, but through approximately 90.

In the example.

Comparatively large spaces are left between .n the passages so that only one half of the suc` tion and *pressure` strokes of the plunger is made use of.

In Fig.-8 I have shown an example'of a a plurality of which are provided for amulti-cylinder engine, each pump supplying fuel for one of the cylinders. As -in this case only durin small portions of the revolution of the p unger fuel is drawn into and vforced out of the cylindrical pocket, the -vacuum and the pressure produced during the suction and pressure strokes would be. ex-

cessive if no provision of relief were adopt-Jv ed. To avoid this the `suction passage 24 extends 'over approximately three quarters of-v the circumferential path of the, cylindrical tends over approximately one quarter of the am nath Thamfnre'hmssure which other- 'pocket y13, while the pressurev passage 23 exw Wise would accumulate within the pocket I3 prior to discharging the fuel from the pump 1s avoided by a forcing back of the fuel into the suction passage during part of the pressure stroke.

. In Fig. 9 I have shown a modification in whichthe pressure passage 23 is disposed not Within the vannular disk but Within the drum 11, as is shown in-broken lines. In this case the passage 23 takes part in the rotation of the drum 11. rIhe stationary disk may be provided with a corresponding port.

While in the examples shown in the figures the' suction and pressure passages are provided at the head side of the drum 11 I Wish it to be understood that my invention is not limited to arranging the said passages at this part of the drum.

In Fig. 10.1, have shown a modification in which the plunge-r 14 is forced out of its pocket and .into contact with disk. 17 by means of a spring 42 which is compressed when theplunger is forced into the pocket by the cam disk .for performing its pressure stroke,.and vWhichduring the suction stroke forces the plunger in contact with the cam disk and at the same time provides the power for drawinginthe fuel. oThis' construction Will be preferable in such cases in which more than tvvo feed plungers are provided Within the rotary drum 11.Y Such pumps which are provided with several pistons are particularly adaptedl for use i in connection with multi-cylinder motors, in which each cylinderis equipped with feeding means of its own, because in such cases instead of separate pumps a single feed pump can be provided for all the cylinders,

the pump being provided with a corresponding number of feed plungers for supplying the fuel to the individual cylinders.

I claim herein as my invention: Y 1. In a combustion engine, the combination, with the cylinder, and the supply for the charge thereto, of a feed pum connected with said supply and with sa1d cyllinder and comprising a stationary casing provided with suction and pressure ducts, and a rotary member provided with a pressure chamber Awhich is adapted upon rotationI alternately to be opened to one and another of said ducts and to be closed by the Wall of the casing and to'have its capacity alternately reduced and increased.

2. In a combustion engine. the combination, with the cylinder, and the supply for 4the charge thereto, of av feed pump connected with said supply and with said cylinder and comprising a casing provided with suction and pressure ducts, a member within said casing provided with a pressure chamber, and mea-ns to impart relative rotary movement to said casing` and member, said pressure chamber being adapted upon ro- Macnee tation alternately to be opened to one and another of said ducts and to be closed by ing suction and pressure ducts .adapted as the cylindrical member rotates alternately to communicate with said cylindrical cham er a piston mounted for reciproca-tion. in said cylindrical chamber, a cam engaging lsaid piston and adapted. upon rotation `of said cylinder member to move the piston in. one direction, and mcansto move the piston 1n the opposite dlrectlon.

4. In` a combustion. engine, the combina! I 1tion, with the cylinder, and the supply for' the charge thereto, of a feed pump conncc'ted with said supply'and With said cylinder and comprising a rotary cylindrical member having a cylindrical chamber disposed length-wise of and eccentric to the axis lof rotation, a stationary 4member having suction and pressure ducts adapted as the cylindrical member rotates alternately to communicate with said cylindrical chamber, a piston mounted for reciprocation inl said cylindrical chamber, an angular-1y disposed-cam engaging said piston and 'adapt-ed upon rotation of said cylinder member to move the piston in one direction, means to movey the piston in the opposite direction, and means to vary the degree of angularity of said cam. l

5. In a combustion engine, thecombination, with the cylinder, and the supply for the charge thereto, of a- :t'eed pump connected with said supply and with `sa1d cylindei and comprising a cylindrical member hav ing a cylindrical Icham'ber,a casing, a cam, means to rotate said cam and casing on the one hand and cylinder member on the other hand relatively to each other, said cylindrical chamber being'disposed eccentrically to and lengthwise of the axis of the relative rotation, a p-iston Within said cylindrical chamber enga ed. by said cam for movement in one dlrection, and means to move said piston in the opposite direction, said .casing being provided with suction and chamber in the said cylindrical member.V

6. In a combustion engine, the combina-I tion, with the cylinder, and the supply for the charge thereto, of a feed pump connected with said supply and with said cylinder and comprising a cylindrical member having a cylindrical chamber, a casing, a

cam, with face angularly disposed to the and casing on the one hand and cylindrical member on the other hand relatively to each other, said cylindrical chamber i being disposed eccentrically to and lengthwise of the axis of the relative rotation, a piston Within said cylindrical chamber engaged. by said 10 cam for movement in one` direction, means to move said piston in the opposite direction, and means to set said cam relatively to the piston in different positions, said casing being provided with suction and pressure ducts adapted as the parts rotate to communicate alternately to the cylindrical chamber in the cylindrical member.

In testimony whereof I hereunto aix my signature.

FRITZ EGERSDORFER. 

